1. Field of the Invention
The present invention relates to the broadcasting of synchronized radio waves in a frequency band covering a predetermined territory by means of a network of adaptive emission antennas.
2. Description of the Prior Art
At present, tall radiating masts are often installed far from towns to emit signals in the decameter, hectometer or kilometer band with a relatively high emitted power. However, the future of large radiating masts near or in towns is compromised for reasons of electromagnetic compatibility. Coupling between the structural portion of the mast and various metal structures that may be situated near the mast, such as steel frames in buildings, metal street lamps and electrical energy transport line pylons constitute induced current sources that are difficult to control when installing antennas.
Apart from environmental constraints with regard to installing radiating masts, the deployment of new radio broadcasting services in frequency bands below 30 MHz is faced with a relatively small number of available frequencies and with the digitization of these bands via the DRM (Digital Radio Mondiale) standard, which requires reorganization of the radio spectrum.
Consequently, a new emission antenna technology is necessary for the partial or total coverage of a predetermined territory such as a country using a single frequency or a single group of frequencies for each radio broadcasting service in a given frequency band.